1. Field of the Invention
The present invention relates to an improved structure and electrical connection assembly for making electrical connections to flexible traces of flexible circuits such as flat flexible cables.
2. Description of the Prior Art
A typical flexible circuit includes a layer of flexible, electrically insulating film carrying an array of conductive traces. The array of traces may be covered by another layer of film. One type of flexible circuit is a flat flexible cable (sometimes called flat flex cable or FFC) in the form of an elongated web or strip with a regular array of conductive traces parallel to one another and parallel to the longitudinal direction of the strip.
The lack of rigidity of flexible circuits and flat flexible cables renders them desirable for use in making electrical connections where flexibility or compliance of the circuit or cable is required. However, connectors used in the past for making electrical connections to the conductive traces of flexible circuits or cables have been subject to difficulties including expense, complexity and difficulty in assembly and use.
U.S. Pat. No. 3,158,421 discloses an electrical connector capable of receiving the edge of a printed circuit board with a flexible circuit frictionally held over the board edge. Openings formed in the flexible circuit permit terminals of the connector to contact conductive areas on the printed circuit board. Conductors of the flexible circuit engage conductive areas of the printed circuit board but are not engaged by terminals of the electrical connector.
U.S. Pat. No. 3,843,951 discloses a connection of an electrical component such as a printed circuit board to a flexible circuit in which the board or other component is forced along with the flexible circuit into a recess in a support member. The support member serves a mechanical and not an electrical function and contact is made between conductors of the flexible circuit and conductors of the printed circuit board or other component.
U.S. Pat. No. 3,923,364 discloses a flexible conductor cable and an assembly for making electrical connections to conductors and to a ground shield layer of the cable. The cable is forced over a mandrel by an electrical connector. The connector includes terminals making electrical contact with the conductors or ground shield layer of the flexible cable.
U.S. Pat. Nos. 3,848,952 and 4,136,917 disclose zero or low insertion force electrical connectors for making edge connections with printed circuit boards. Connectors of this general class are widely used, but have not heretofore been capable of effectively making electrical connections with flexible circuits.